The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Michael G Ganzle - One of the best experts on this subject based on the ideXlab platform.

  • phenolic acids and Flavonoids in nonfermented and fermented red sorghum sorghum bicolor l moench
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Louise Svensson, Bonno Sekwatimonang, Daise Lopes Lutz, Andreas Schieber, Michael G Ganzle
    Abstract:

    This study aimed to identify phenolic acids and Flavonoids in the red sorghum variety PAN 3860 and to determine changes in their concentrations during fermentation with lactobacilli. Sorghum sourdoughs fermented with two binary strain combinations, Lactobacillus plantarum and Lactobacillus casei or Lactobacillus fermentum and Lactobacillus reuteri, were compared to chemically acidified controls. Four glycerol esters were tentatively identified, caffeoylglycerol, dicaffeoylglycerol, coumaroyl-caffeoylglycerol, and coumaroyl-feruloylglycerol, that have previously not been detected in sorghum. Chemical acidification resulted in hydrolysis of phenolic acid esters and Flavonoid glucosides. During lactic fermentation, phenolic acids, phenolic acid esters, and Flavonoid glucosides were metabolized. Analysis of ferulic acid, caffeic acid, and naringenin-glucoside contents in single-strain cultures of lactobacilli demonstrated that glucosidase, phenolic acid reductase, and phenolic acid decarboxylase activities co...

  • Phenolic Acids and Flavonoids in Nonfermented and Fermented Red Sorghum (Sorghum bicolor (L.) Moench)
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Louise Svensson, Daise Lopes Lutz, Andreas Schieber, Bonno Sekwati-monang, Michael G Ganzle
    Abstract:

    This study aimed to identify phenolic acids and Flavonoids in the red sorghum variety PAN 3860 and to determine changes in their concentrations during fermentation with lactobacilli. Sorghum sourdoughs fermented with two binary strain combinations, Lactobacillus plantarum and Lactobacillus casei or Lactobacillus fermentum and Lactobacillus reuteri , were compared to chemically acidified controls. Four glycerol esters were tentatively identified, caffeoylglycerol, dicaffeoylglycerol, coumaroyl-caffeoylglycerol, and coumaroyl-feruloylglycerol, that have previously not been detected in sorghum. Chemical acidification resulted in hydrolysis of phenolic acid esters and Flavonoid glucosides. During lactic fermentation, phenolic acids, phenolic acid esters, and Flavonoid glucosides were metabolized. Analysis of ferulic acid, caffeic acid, and naringenin-glucoside contents in single-strain cultures of lactobacilli demonstrated that glucosidase, phenolic acid reductase, and phenolic acid decarboxylase activities contributed to polyphenol metabolism. This study demonstrates that microbial fermentation of sorghum affects the content of polyphenols and can influence the nutritional value and antimicrobial activity of sorghum.

Weihua Xiao - One of the best experts on this subject based on the ideXlab platform.

  • isolation and purification of Flavonoid glucosides from radix astragali by high speed counter current chromatography
    Journal of Chromatography B, 2009
    Co-Authors: Weihua Xiao
    Abstract:

    Abstract High-speed counter-current chromatography methods, combined with resin chromatography were applied to the separation and purification of Flavonoid glycosides from the Chinese medicinal herb, Radix Astragali. Five Flavonoid glycosides, namely calycosin-7-O-β- d -glucoside, ononin, (6aR, 11aR)-9,10-dimethoxypterocarpan-3-O-β- d -glucoside, (3R)-2′-hydroxy-3′,4′-dimethoxyisoflavan-7-O-β- d -glucoside and calycosin-7-O-β- d -glucoside-6′′-O-acetate, were obtained. Among them, calycosin-7-O-β- d -glucoside-6′′-O-acetate was preparatively separated from Radix Astragali for the first time. Their structures were identified by ESI–MS, 1H NMR, 13C NMR, and 2D NMR.

  • Isolation and purification of Flavonoid glucosides from Radix Astragali by high-speed counter-current chromatography.
    Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2009
    Co-Authors: Weihua Xiao
    Abstract:

    High-speed counter-current chromatography methods, combined with resin chromatography were applied to the separation and purification of Flavonoid glycosides from the Chinese medicinal herb, Radix Astragali. Five Flavonoid glycosides, namely calycosin-7-O-beta-d-glucoside, ononin, (6aR, 11aR)-9,10-dimethoxypterocarpan-3-O-beta-d-glucoside, (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-d-glucoside and calycosin-7-O-beta-d-glucoside-6''-O-acetate, were obtained. Among them, calycosin-7-O-beta-d-glucoside-6''-O-acetate was preparatively separated from Radix Astragali for the first time. Their structures were identified by ESI-MS, (1)H NMR, (13)C NMR, and 2D NMR.

Louise Svensson - One of the best experts on this subject based on the ideXlab platform.

  • phenolic acids and Flavonoids in nonfermented and fermented red sorghum sorghum bicolor l moench
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Louise Svensson, Bonno Sekwatimonang, Daise Lopes Lutz, Andreas Schieber, Michael G Ganzle
    Abstract:

    This study aimed to identify phenolic acids and Flavonoids in the red sorghum variety PAN 3860 and to determine changes in their concentrations during fermentation with lactobacilli. Sorghum sourdoughs fermented with two binary strain combinations, Lactobacillus plantarum and Lactobacillus casei or Lactobacillus fermentum and Lactobacillus reuteri, were compared to chemically acidified controls. Four glycerol esters were tentatively identified, caffeoylglycerol, dicaffeoylglycerol, coumaroyl-caffeoylglycerol, and coumaroyl-feruloylglycerol, that have previously not been detected in sorghum. Chemical acidification resulted in hydrolysis of phenolic acid esters and Flavonoid glucosides. During lactic fermentation, phenolic acids, phenolic acid esters, and Flavonoid glucosides were metabolized. Analysis of ferulic acid, caffeic acid, and naringenin-glucoside contents in single-strain cultures of lactobacilli demonstrated that glucosidase, phenolic acid reductase, and phenolic acid decarboxylase activities co...

  • Phenolic Acids and Flavonoids in Nonfermented and Fermented Red Sorghum (Sorghum bicolor (L.) Moench)
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Louise Svensson, Daise Lopes Lutz, Andreas Schieber, Bonno Sekwati-monang, Michael G Ganzle
    Abstract:

    This study aimed to identify phenolic acids and Flavonoids in the red sorghum variety PAN 3860 and to determine changes in their concentrations during fermentation with lactobacilli. Sorghum sourdoughs fermented with two binary strain combinations, Lactobacillus plantarum and Lactobacillus casei or Lactobacillus fermentum and Lactobacillus reuteri , were compared to chemically acidified controls. Four glycerol esters were tentatively identified, caffeoylglycerol, dicaffeoylglycerol, coumaroyl-caffeoylglycerol, and coumaroyl-feruloylglycerol, that have previously not been detected in sorghum. Chemical acidification resulted in hydrolysis of phenolic acid esters and Flavonoid glucosides. During lactic fermentation, phenolic acids, phenolic acid esters, and Flavonoid glucosides were metabolized. Analysis of ferulic acid, caffeic acid, and naringenin-glucoside contents in single-strain cultures of lactobacilli demonstrated that glucosidase, phenolic acid reductase, and phenolic acid decarboxylase activities contributed to polyphenol metabolism. This study demonstrates that microbial fermentation of sorghum affects the content of polyphenols and can influence the nutritional value and antimicrobial activity of sorghum.

Jaromir Budzianowski - One of the best experts on this subject based on the ideXlab platform.

  • separation of Flavonoid glucosides from their galactosidic analogues by thin layer chromatography
    Journal of Chromatography A, 1991
    Co-Authors: Jaromir Budzianowski
    Abstract:

    Abstract Particular problems in Flavonoid analysis such as the separation of mixtures of glucosyl and galactosyl analogues appears to be solvable by means of thin-layer chromatography in classical flat chambers. Each of the nine pairs of such analogues tested, including flavonol 3-O-glycosides (three pairs), flavonol 3-O-diglycosides (two pairs), mono-C-glycosylflavones (one pair), di-C-glycosylflavones (one pair) and C,O-glycosylflavones (two pairs) could be resolved into individual components in at least one of the nine chromatographic systems described. The method is recommended for homogeneity control of C-glycosylflavones and any Flavonoid which releases both glucose and galactose on hydrolysis.

Stefan Martens - One of the best experts on this subject based on the ideXlab platform.

  • identification of a saccharomyces cerevisiae glucosidase that hydrolyzes Flavonoid glucosides
    Applied and Environmental Microbiology, 2011
    Co-Authors: Sabine Schmidt, Sandra Rainieri, Simone Witte, Ulrich Matern, Stefan Martens
    Abstract:

    Baker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-β-glucoside revealed considerable β-glucosidase activity, which impairs any strategy to generate or modify Flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in the S. cerevisiae genome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic α- or β-glucosides identified three efficient β-glucosidases (EXG1, SPR1, and YIR007W), which were further assayed with natural Flavonoid β-glucoside substrates and product verification by thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Preferential hydrolysis of 7- or 4′-O-glucosides of isoflavones, flavonols, flavones, and flavanones was observed in vitro with all three glucosidases, while anthocyanins were also accepted as substrates. The glucosidase activities of EXG1 and SPR1 were completely abolished by Val168Tyr mutation, which confirmed the relevance of this residue, as reported for other glucosidases. Most importantly, biotransformation experiments with knockout yeast strains revealed that only EXG1 knockout strains lost the capability to hydrolyze Flavonoid glucosides.

  • Identification of a Glucosidase from Saccharomyces cerevisiae Hydrolyzing Flavonoid glucosides
    Applied and Environmental Microbiology, 2011
    Co-Authors: Sabine Schmidt, Simone Witte, Ulrich Matern, Sandra Raineri, Stefan Martens
    Abstract:

    Baker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-β-glucoside revealed considerable β-glucosidase activity, which impairs any strategy to generate or modify Flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in the S. cerevisiae genome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic α- or β-glucosides identified three efficient β-glucosidases (EXG1, SPR1, and YIR007W), which were further assayed with natural Flavonoid β-glucoside substrates and product verification by thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Preferential hydrolysis of 7- or 4′-O-glucosides of isoflavones, flavonols, flavones, and flavanones was observed in vitro with all three glucosidases, while anthocyanins were also accepted as substrates. The glucosidase activities of EXG1 and SPR1 were completely abolished by Val168Tyr mutation, which confirmed the relevance of this residue, as reported for other glucosidases. Most importantly, biotransformation experiments with knockout yeast strains revealed that only EXG1 knockout strains lost the capability to hydrolyze Flavonoid glucosides.